Continuation of combined clinical and immunologic study of hay fever is proposed. Matched groups of patients will be compared in control studies of immunotherapy with standard or improved pollen extracts. Clinical evaluation by symptom diary and laboratory evaluation by challenge tests, enumeration of inducer and suppressor T cells, functional tests of antibody synthesis by peripheral blood mononuclear cells, basophile histamine release and serum IgE, and IgG antibody levels will be correlated.